arrayCopy.js

define([],
       function() {

var testArray;
try {
    testArray = new Uint8Array(1);
} catch (x) {}
var hasSlice = false; /* (typeof testArray.slice === 'function'); */ // Chrome slice performance is so dire that we're currently not using it...

function arrayCopy(src, srcOffset, dest, destOffset, count) {
    if (count == 0) {
        return;
    }
    if (!src) {
        throw "Undef src";
    } else if (!dest) {
        throw "Undef dest";
    }

    if (srcOffset == 0 && count == src.length) {
        arrayCopy_fast(src, dest, destOffset);
    } else if ( src.subarray ) {
        arrayCopy_fast(src.subarray(srcOffset, srcOffset + count), dest, destOffset);
    } else if (src.BYTES_PER_ELEMENT == 1 && count > 100) {
        arrayCopy_fast(new Uint8Array(src.buffer, src.byteOffset + srcOffset, count), dest, destOffset);
    } else {
        arrayCopy_slow(src, srcOffset, dest, destOffset, count);
    }

}

function arrayCopy_slow(src, srcOffset, dest, destOffset, count) {

    // dlog('_slow call: srcOffset=' + srcOffset + '; destOffset=' + destOffset + '; count=' + count);

     for (var i = 0; i < count; ++i) {
        dest[destOffset + i] = src[srcOffset + i];
    }
}

function arrayCopy_fast(src, dest, destOffset) {
    dest.set(src, destOffset);
}


return arrayCopy;

});